The present invention relates to a trailing edge device of an aircraft wing, and more specifically, a blended cutout flap of a trailing edge device that reduces jet-flap interaction noise.
An aircraft wing typically includes a high-lift system with flaps, which are disposed in an extended position during specific operations of the aircraft. The aircraft wing also includes some elements of a flight control system of the aircraft. FIGS. 1 and 2 are partial schematic diagrams illustrating conventional aircraft wings. As shown in FIG. 1, a portion of an aircraft 50 having a fuselage 51 and a wing 100 with high-lift devices are provided. The high lift devices may include deployable slats 101 positioned toward a leading edge of the) wing 100 and multiple trailing edge devices positioned toward a trailing edge of the wing 100. The trailing, edge devices include an outboard aileron 103, an outboard flap 105, an inboard aileron 107, and an inboard flap 109. The outboard and inboard ailerons 103 and 107 are typically used for roll control of the aircraft 50 while the outboard and inboard flaps 105 and 109 are used to control the lift of the aircraft 50 during takeoff and landing operations. The ailerons 103 and 107 are hinged devices that are un-gapped when in their deployed position. When the flaps 105 and 109 are deployed, they rotate and move in an aft direction to open a gap relative to the wing 100 (as depicted by arrows 111 and 113). Since the motion path of the inboard flap 109 (as indicated by arrow 111) converges with the motion path of the outboard flap 105, the inboard aileron 107 located between the flaps 105 and 109 does not move aft when deployed (as indicated by arrow 115).
As shown in FIG. 2, a portion of an aircraft 50 having a fuselage 51 and a wing 200 with high-lift devices are provided. The high lift devices may include deployable slats 201 positioned toward a leading edge of the wing 200 and multiple trailing edge devices. The trailing edge devices include an outboard aileron 203, an outboard flap 205, a flaperon 207, and an inboard flap 209. The inboard flap 209 and the outboard flap 205 rotate, and the inboard flap 209 travels aft (as depicted by arrow 211), while the outboard flap 205 moves along a motion path as depicted by arrow 213. The flaperon 207 may also move aft to a gapped position as depicted by arrow 215 which is parallel to the movement of the outboard and inboard flaps 205 and 209. Inboard and outboard spoilers 60 and 61 may also be used to control the size of the gaps between the wings and the flaps 205 and 209. The flaperon 207 may be deflected for roll control and lift control.
The engine (not shown) of the aircraft 50 is typically integrated close to the wing 100, 200 and many factors such as weight and ground clearance may cause the wing 100, 200 to become in close proximity to an exhaust flow of the engine. During operation of the high-lift system, as flight control surfaces are deployed, the proximity to the exhaust flow of the engine and the wing's 100, 200 control surfaces is increased. The proximity of the engine to a trailing edge device (e.g., the flaps 109, 209, aileron 107, or flaperon 207) may produce unwanted jet-flap interaction noise that is associated with lower frequencies and radiates strongly when the aircraft 50 is moving in the forward direction. As shown in FIGS. 1 and 2, the trailing edge device e.g., the aileron 107 and the flaperon 207) are typically formed in a trapezoidal shape including a straight trailing edge 107a, 207a which may contribute to the jet-flap interaction noise. A conventional method of decreasing jet-flap interaction noise has been to simply increase the separation between the jet exhaust and the wing (and deflected trailing edge devices). This increased separation results in a longer pylon, longer landing gear (to maintain ground clearance), and, in general, results in increased weight for the aircraft and other undesirable performance parameters. For the majority of aircraft applications, a closer integration of engine and wing will be more desirable if the jet-flap interaction noise can also be minimized.